Just copy the URL from your browser over to here, for example http://www.youtube.com/watch?v=6W5Iip6iDLY" onclick="window.open(this.href);return false;
Then either highlight it & click the yt button or add the tags manually so you end up with
Code: Select all
[yt]http://www.youtube.com/watch?v=6W5Iip6iDLY[/yt]